By Ron Cowen
Eight years ago, astronomers made an astonishing discovery: The rate at which the universe is expanding, assumed to have been steadily slowing since the Big Bang, is in fact speeding up. The entity revving up cosmic expansion remains elusive (SN: 5/22/04, p. 330: Dark Doings), but scientists have dubbed it dark energy. This week, a team reported gains in its efforts to understand and describe it.
The work provides new hints that dark energy might be distributed uniformly throughout space and time (SN: 2/28/04, p. 132: Available to subscribers at Wrenching Findings: Homing in on dark energy). It further suggests that dark energy closely resembles the cosmological constant that Albert Einstein introduced into his theory of gravity in 1917 but quickly abandoned. In Einstein’s theory, the constant can either add to or oppose gravity’s tug.